If there’s a silver lining to the endless cold and snow of this winter, it’s that struggling forests are getting a reprieve from the toll of invasive insects.

For decades, winters have been too warm to kill off insects, creating a never-ending population boom that’s been chewing up trees coast to coast.

This year, forests got a reprieve as it finally became cold enough to kill most of the insects. For example, emerald ash borer populations are down 80% in the upper Midwest, according to the U.S. Forest Service. They have been decimating ash trees across their range.

90% of the hemlock woolly adelgid are dead, which have been killing off hemlock trees further and further north in the East; corn earworm, found in nearly every state; and cottony cushion scale that destroys citrus crops. Even the gypsy moth population could be temporarily controlled – it works on some 80 species of trees and has been spreading west from the Northeast.

One holdout seems to be the pine beetle which, since the late 1990s, has devastated 6.6 million acres of lodgepole pine forests in Colorado. Even temperatures of minus 20 degrees aren’t cold enough to kill it. By the time cold arrived in mid-December, the insects were dormant – only prolonged minus 30 degree temperatures could get them.